Supplemental device for attachment to an injection device

Abstract

A supplemental device for attachment to an injection device, the supplemental device having a housing containing at least two electromechanical switches each having an open state and a closed state and a protrusion associated with each switch configured to protrude from the housing so as to contact a rotatable surface of the injection device while the supplemental device is attached to the injection device; and a processor arrangement configured to detect a change in the state of each of the switches; and to determine a direction of rotation of the rotatable surface of the injection device from the detected state changes.

The invention claimed is: 
     
       1. A supplemental device for attachment to an injection device, the supplemental device comprising:
 a housing containing a first electromechanical switch and a second electromechanical switch, each of the first and second electromechanical switches having a first state and a second state and an associated actuator, wherein the actuators associated with each of the first and second electromechanical switches are arranged to protrude from the housing so as to contact a rotatable surface of the injection device during axial and rotational movement of the rotatable surface; and 
 a processor arrangement configured to:
 detect a change in the state of each of the first and second electromechanical switches; and 
 determine a direction of rotation of the rotatable surface of the injection device from the detected state changes, 
 
 wherein the rotatable surface is configured to cause the state of each of the first and second electromechanical switches to change between the first state and the second state during rotation of the rotatable surface. 
 
     
     
       2. The supplemental device according to  claim 1 , wherein the rotatable surface comprises troughs and crests and wherein the first state of each of the first and second electromechanical switches represents when the respective actuator of each of the first and second electromechanical switches is located a trough and the second state represents when the respective actuator of each of the first and second electromechanical switches is located on a crest. 
     
     
       3. The supplemental device according to  claim 1 , wherein the first and second electromechanical switches are arranged to protrude from the housing so as to contact the rotatable surface at different relative circumferential positions while the supplemental device is attached to the injection device. 
     
     
       4. The supplemental device according to  claim 1 , wherein the actuators are arranged at the same longitudinal positions relative to the rotatable surface. 
     
     
       5. The supplemental device according to  claim 1 , wherein the processor arrangement is configured to determine the direction of rotation of the rotatable surface from an order in which the states of the first and second electromechanical switch change. 
     
     
       6. The supplemental device according to  claim 1 , wherein the first state is an open state and the second state is a closed state. 
     
     
       7. The supplemental device according to  claim 1 , wherein the supplemental device is configured such that, when the supplemental device is attached to the injection device and when the rotatable surface is in a rotational position representing an integer dose value, the first and second electromechanical switches both have either the first state or the second state. 
     
     
       8. The supplemental device according to  claim 7 , wherein an increase or decrease of one integer dose unit in the rotational position of the rotatable surface causes the state of the first and second electromechanical switches to change from an initial state to the opposite state and back to the initial state. 
     
     
       9. The supplemental device according to  claim 7 , wherein an increase or decrease of one integer dose unit in the rotational position of the rotatable surface causes the state of the first and second electromechanical switches to change from an initial state to the opposite state. 
     
     
       10. The supplemental device according to  claim 7 , wherein an increase or decrease of one integer dose unit in the rotational position of the rotatable surface causes the state of one of the first and second electromechanical switches to change from an initial state to the opposite state while the state of the other of the first and second electromechanical switches remains the same. 
     
     
       11. The supplemental device according to  claim 1 , wherein the supplemental device is configured such that, when the supplemental device is attached to the injection device having a corrugated rotatable surface and when the rotatable surface is in a rotational position representing an integer dose value, the first electromechanical switch has the first state and the second electromechanical switch has the second state. 
     
     
       12. The supplemental device according to  claim 11 , wherein an increase or decrease of one integer dose unit in the rotational position of the rotatable surface causes the state of the first and second electromechanical switches to change from their respective initial states to the opposite states and back to their initial states. 
     
     
       13. The supplemental device according to  claim 11 , wherein an increase or decrease of one integer dose unit in the rotational position of the rotatable surface causes the state of the first and second electromechanical switches to change from their respective initial states to the opposite states. 
     
     
       14. The supplemental device according to  claim 11 , wherein an increase or decrease of one integer dose unit in the rotational position of the rotatable surface causes the state of one of the first and second electromechanical switches to change from an initial state to the opposite state and back to the initial state and causes the state of the other of the first and second electromechanical switches to change from an initial state to the opposite state.